David

Thank you.



Originally It is recomended a MK 150cc fuel tank, but I used the MK 190cc oval type fuel tank for the aurora 25.
And a.u.w without fuel is 1395g+ 55g(prop + spinner ) with 1600mAh 6V 5cell Ni-MH battery.

I saw a Hatory header for Arrow 20 (OS 25vf abc), but never find the MK arrow 20 in Korea & Japan at least today.
I like MK SKYMASTER 20 so much , but next project is other one,


Here is one complete set of MK SKYMASTER 20 of mine,(thanks for providing glass deck for me)



JHMIN

http://www.rcuniverse.com/forum/atta...mentid=2042563http://www.rcuniverse.com/forum/atta...mentid=2042564http://www.rcuniverse.com/forum/atta...mentid=2042565http://www.rcuniverse.com/forum/atta...mentid=2042566http://www.rcuniverse.com/forum/atta...mentid=2042567http://www.rcuniverse.com/forum/atta...mentid=2042568http://www.rcuniverse.com/forum/atta...mentid=2042569http://www.rcuniverse.com/forum/atta...mentid=2042570

TS,

thanks for your PM reply. I PM'd you back. Please follow up by email if you don't mind.

I hope it's of some use.

Good to know! I take it you were able to source a kit then?

Nice. I know that it is possible to produce nice parts with CNC routers. I just felt that this kit was a little "coarse". Then again, I'm used to the accuracy of laser.

We might be on our way to solving this. The OK Model (Pilot) kits are very easy and straight forward to build and given Hanno's simpler later designs they are ideally suited to each other. The one thing that I will change in the CAD re-design is the "weight" of the fuses. The wings and empennage are standard and fine in weight but the fuses are built like tanks with too much birch plywood. If one were to use glow 25-35 size engines most all ply can be swapped for lite ply (half the weight) and if they are going to be e-powered, much of the 1/8" lite ply (doublers in particular) can be substituted for 1/8" balsa. I expect to cut weight down by 0.5 - 0.75 lbs all up and be able to carry a couple more ounces (7-8) of fuel if needed in the larger models (e.g., Mystic) if using a 35 or even a light 40 size engine. The mid-wing designs (Mystic) will likely use plug-in wings while the low wing (Curare, Calypso, SF, SS, etc.) will be standard one piece wings. All models will be designed with e-tracts in mind whether conventional (Calypso forward) or trike (Magic backward).

David

JH,

I hope you're enjoying your Curare's!

The 190 cc (~6.5 oz) tanks for the larger MK and OK 20 size birds (Aurora, Cosmos, Joker, Kingbird, Mystic, Rubin, etc.) makes a lot of sense. I'm hoping that in re-designing them I might be able to fit a 7 to 8 oz tank (200 - 236 cc) particularly if they have plug-in wings (Aurora, Cosmos, Mystic, Arrow?). For the smaller guys (Curare, Magic, Mattlas, Skymaster) a 5-6 oz (150 - 175 cc) seems more than enough as these are using 25-32 size engines instead of 35-40 size.

Yes, I'm not certain but I suspect that MK had plans to do the Arrow 20 and maybe Hatori got ahead of the plans (literally) making the appropriate header for the 25 VF. In any case it should be a standard 1/2" or 1" fuse top header. An Arrow 20 would be just too cool on the fight line! Now there is even a very powerful NovaRossi 28 RE (not a Japanese OS but given the Arrow is a European design, an Italian engine seems fitting. :))

I guess that makes two of us - SM20 perhaps my favorite RE design with the Arrow 20. One day I hope to have a pair on the flight line side by side. But you'll probably get there much before me! if I only spent more time building and flying and quit all this conservation effort stuff! :rolleyes:

One of my ideas (and I'm not the only one) has been to modify the Magic 20 design to a RE (Skymaster like) inverted engine setup - like its bigger 40 and 60 size siblings. But there is much to do already. Working on a Mystic 45 CAD design at the moment. Hope to be prototyping it before years end!

I'm eager to see and hear about your next project.

David

One of our club members passed away and in the estate was a completed Curare 20 with a OS .25. I did some trading for it with another member and Finally have my hands on it. I pulled the engine and installed a K&B .21 RE with a Magic Muffler and lots of tiny JR $ervos to run the retracts and all flight surfaces with the little 700 MAH LiFe from Hobby king. 3 pounds 4 oz I think it really goes like stink I am sure this is much faster than intended with that little piped powerhouse! The engine really doesn't have much mid range, pretty much on and off the pipe.
I had some flutter issues but gap seals fixed that issue. Really a fun plane to do Old School pattern flying.
I found out that it had one flight probably in the 80's then it was put up until I got the plane I am honored to be able to fly the plane and it really is a blast from the past.
Sparky

Pictures Sparky, or it didn't happen!:p
Chris...

Help with nose wheel retract, please..?
 

Good evening, JHMIN...

My apologies for awakening this (excellent...) topic, asleep for far too long, but I have an issue that you may be able to help me with, if you would. I am building a Curare 20 from a short kit, for electric motorisation. I've received the chosen retracts for this 'plane, the same set as you have used (Turnigy MCR All Metal Retract System...). I want to install 3mm legs, and had no problems removing the original 3mm 'leg' from the two wing units, by backing off the two grub screws 'hidden' in their bronze bushings.. Not so easy for the nose wheel unit, though. There are no grub screws in the bushings; the 'leg' is held in place by the steering collar. This I was able to remove easily enough, but the 'leg' still refuses to come out. It appears, from close inspection, as if the inner end of the 'leg' has a flange, which prevents forward movement, and therefore extraction.
I see from your (excellent...) photos that you have succeeded in fitting a 3mm nose wheel leg, so I assume that you managed to remove the original 'leg'. Do you remember how you did this..? Did you have the same issue of the inner flange preventing it from coming out..? I don't wish to start disassembly of this unit if it can be avoided, but will do so, if it's the only way of removing this 'leg'. Did you have to resort to such measures, or have I overlooked something..?
Thanks in advance for any information or assistance you're able to offer, and warm thanks for having posted, all that time ago, such an excellent topic; meanwhile...

Have a nice day

Douglas

I got my Curare at an estate sale. Mechanical retracts (Proline maybe) replaced the engine and radio. I have a K&B .21 FIRE with a magic muffler. 3.5 pounds and 17,000 RPM on a 8x6. 30% Nitro. I had flutter problems but solved it with sealing the hinge lines. It is fast as heck!


https://cimg6.ibsrv.net/gimg/www.rcu...09846a720.jpeg